Reversing valve-gear.



C. J. PILLIOD.

REVERSING VALVE GEAR. APPLICATION FILED DEC.28. 1912.

Patented Oct. 23, 1917.

3 SHEETSSHEET 1- c. J. PILLJOD. REVERSING VALVE GEAR.

APPLICATION FILED DEC.28. I912.- 1,43,70B Patented Oct. 23,1917.

3 SHEETS-SHEET 2.

C. J. PILLIOD.

REVERSING VALVE GEAR.

APPLICATION FILED DEC.28. i912. 1,243,760, Patented Oct. 23,1917.

' 3 SHEETS-SHEET 3.

errennns :r. rInLIon, or TOLEDO, orrro,

5-. FATE nssrenon r0 THE PILLIOD 'nnorn'nns nnvnn'srive VALVE-GEAR.

Specification of Letters Patent.

Patented Oct. 23, 191' a.

Application'filed December 28, 1912. Serial No. 739,019.

To all whom it mag l concern Be it known that I; CHARLES J. PILLIOD, acitizen of: the United Statesof America, residing at Toledo; in thecounty of Lucas and State of' Ohio, have invented certain new and usefulImprovements in Reversing Valve-Gears, of which the following is aspecification, reference being had=therein to the accompanying drawings.

The invention relates to valve gears more particularly designed for useon locomo tives and it is the primary object of the invention to obtaina construction of reversing gear inwhich an equal valve travel uponopposite sides of the center of movement is obtainediin all positions ofadjustment of the cut-off. V

In the operation of valve gears employing angularly-moving connectingrods, the simple harmonic movementproducedby the crank or eccentric ismore orlessdistortedy due to the angularity of-the rod. This results ina greater movement on one sideof the center thanupon the other side,-and where a reversinggearisg-em'ployed it has been heretofore impossibleto fully correctthe-distortion. My improved construction isone which theerrors due to rod angularity are so corrected or minimized that forallpractical purposesthe movementof the valve is equidistant from thecenter on opposite sides thereof'in both forward and re- ,verse and inall positions of adjustmentof cut-off.

My improvement is applicableto various specific constructions ofvalvegears, but as shown, is applied to a locomotive valve gearemploying what isknown in theart as the Marshall. reverse.

In the drawings; Figure l is a side elevation; V Fig. -2-is a plan viewof the gear on'one side of the locomotive- Fig 3 is a diagramillustratingthe prin-. ciple of operation. 7

Fig, 4L is a=diagrammatic view ofa modn fication,

Fig. .5 is a vertical section of a detail. The specific constructionshown in Figs. 1 and 2 is ofthat type in which the movement of-the valveis produced partly; by a connection, 5 to the cross-head 1 of Ithecorrespondingcyli-nden and partly by aconnection to the cross-head ofthecylinder on the opposite side of; the locomotive. This is equivalentto the operation of the valvefrom two cranks set at an angle of 90apart-and operating through 'angularly movable rods. In detail, A- isthe crosshead-on one side of the locomotive, which is connect'edby alink' B with a lever C, which in' turn'is connectedby a rod D- to alever E substantially parallel to the lever O and fulcrumed inacrosshead F, slidable in ways G and connected to the valve rod H. Theopposite end of the lever-E is connected by a rod' Ito the rodO havingone end connected to a rock-arm P upon a rock-shaft Q by means of areverse gear of the Marshall type, which in the present instancecomprises the bell-crank lever J connected'with the rod I and having itsactuating arm connected by a link K with a pair of linksL on oppositesides thereof, which links in turn are pivotally connected to a pivotedyoke M5.adjustablethrough thero'd N to, different angular positions..The pivotal connection of'the links K and L also forms a connection fortheirod O. This rock-shaft extends across the locomotive frame and isactuated by a lever, on the opposite side of said; frame correspondingto the lever C, and actuated in a similar manner from the cross-' heado-f'the engine on that side of the locomotive. The lever O is alsoconnected to a rock-shaft Q5, which extendsacross parallelyto the'rockeshaft Q, and is connected byelements not shown similar to theparts D E F G H I J KL M N O and P forming the valve-gear for theopposite engine. a I

With the construction v as above described, the valverod H isactuated-by the lever E through the combined action of the rods D and I.The former imparts to the valve all' necessarylap and lead movement,-while the latter, through adjustment of the rod N and yoke -'M,will'impart a variably accelerating movement, determining the degree ofopen: ing. of the yalve. v Thuscwhen the rod N and yoke M-is in thecentral position shown in Fig. 1, no movement is impartedto thebell-crank J and rodI, for the reason that thelinks K and L have theiraXes or pivots substantially? inv alineinent and consequently themovement imparted to the links. L through th'e'medium of therodO androck arm Pwill only, result in swinging the link K withoutv actuatingthe bell-crank. On the other hand, if the rod N is actuated to aol justthe yoke M to either side of' its central positions, the axis of thepivotal connection between links L and yoke M is thrown out of alinementwith the axis of the pivotal link K and bell-crank J, whereby a movementis imparted to the bell-crank, varying in accordance with the positionof adjust ment of the yoke. This movement is versed when the yoke isadjusted upon the opposite side or the center and correspond inglyvaried according to the position of adjustment.

As has been previously stated, it is the primary object of the inventionto obtain equal valve movement upon opposite sides of the center in allpositions of adjustment of the yoke, and also equal movement when theyoke is adjusted to corresponding positions upon opposite sides of itsneutral point. This has not been heretofore accomplished with the typeof reversing gear such as above described, as irregularities areintroduced by the angular movement of the rods, which give unequalmovements both in respect to the opposite sides of the center ofmovement of the valve and also with respect to opposite sides of thereversing mechanism. I have overcome this defect by introducing acorrective in the mechanism in-' termediate the crosshead and thebell-crank lever J, the result being the correction or the minimizing oferrors to a point where for all practical purposes the valve movement isuniform.

The principle of my improved construction is best illustrated in thediagram, Fig. 3. As therein shown, the are described by the swinging ofthe rock-arm P on the rockshaft Q has unequal segments in the movementproduced by the first 90 and the second 90 of movement of the enginecrank on opposite sides of its dead center. In the former, the segmentis elongated by the straightening of the rod, and in the latter isproportionately shortened so that the position of the rock-arm P, whenthe engine crank is on dead center, is indicated at a Fig.

3, and the length of the are from the initial point Z) is greater thanthe arc to the opposite end of movement ,0. equality, the arm P, insteadof being arranged parallel to the link K, is angularly oflset asindicated, and this offset produces in the movement imparted to saidlink through the connecting rod U, a correction of any inequalityexisting between the arcs a 7) and the arcs a c. The movement isaffected by the angularity of the rod 0 in different positions ofadjustment of the yoke M, but by properly selecting the relative lengthsof the radius arms and the posi tions of. the centers of movement, analmost perfect correction is obtained. Thus in the diagram Fig. 3, theare d 6 describes the path of movement of the swinging link L. 'when theyoke M is adjusted to its extreme To correct this in-' -position. to theright of the center, indicated the bell-crank J. 'As shown in Fig. 3 thelines representing the bell-crank J are positioned between the yoke Mand the rock-arm P, the equal valve movement being fully as wellillustrated as it the bell-crank were represented in the position asshown in Figs. 1, 2 and 4. i

It will be observed by inspecting this Fig. 3 that a series of points mm, etc., set oil in the are 6 0, corresponding to equal angularmovements of the actuating engine crank, are irregular or unequal in thetwo portions of said are a; b and a 0. It will also be seen that thearcs n n, etc., described by the angular movement of the rod 0 from eachof the points m m, etc., will intersect the arcs (Z c and g 72,, andthat the series of points produced by such intersections will besubstantially regular on opposite side of the intersecting point 0 ofsaid arcs (Z 6 and g it. Furthermore, the point of intersection in thearcs (Z 0 and h 0 are respectively equi distant from the same point inthe arc j is, and in like manner the points in the arcs e oand g o arerespectively equidistant from the same point in said are jic. This willproduce an equal angular movement of the bellcrank J with a givenmovement of the rock arm P whether the yoke M is adjusted to the point ior to the point '5, so that in re versing the gear the valve movementwill equal but opposite. This is also true for every point ofintermediate adjustment of. the yoke M upon opposite sides of itscenter. Again the angular movement imparted to the bell-crank J bythetravel of the link it: to successive points along the are d 0 is equalto the movement of said link along the are e 0 to the correspondingpointtherein; which means that the movement is equal and correspondingupon opposite sides of the center of movement of the bell-crank.

The correction of distortion due to angularity having been effected inthe movement of the bell-crank J, it is obvious that this movement canbe imparted without further distortion to the valve rod through themedium of the rod I and lever E. Briefly reviewing the entire movementfrom the engine crank-shaft to the valve, it will be seen that thesimple harmonic movement, of the crank is first distorted through theangular movement of the connecting rod upon the opposite side of thelocomotive. This distorted movement is transmitted through the link Band lever C to the rock-shaft Q, and to the rock-arm P upon the oppositeend thereof. Correction of the distortion is then effected by theangular olfsetting of the rock-arm P, and the proportion and relativearrangement of elements between the same and the bell-crank J. Thecorrected movement is transmitted from the bell-crank through the rod Ito the lever E and from the latter through the cross-head F and rod H tothe valve.

My improvement is also applicable to the type of valve gear in which thevalve is actuated solely from the engine on one side of the locomotivewhich it controls. This, as shown in Fig. 4, includes a crank S attachedto the crank pin T of the locomotive and having a pin U which isarranged at an angle of 90 about the crank from the pin T. This pin U isconnected by a rod V with an extension W of the rock-arm P, and actuatesthe latter in the same manner as where actuated by the crank on theopposite side of the locomotive. The same distortions due to theangularity of the rod V are introduced in the movement of the rockarm P,but these are corrected by the mechanism as previously described.

l/Vhat I claim as my invention is:

1. The combination with a reciprocating piston engine having a rotarypart, of a valve gear including a rock arm and means including aconnecting rod and cross-head for imparting angular motion from therotarypart to said rock arm, an engine valve, means connecting said rockarm with the engine valve including a reverse gear of the Warshall type,said rock arm being at such I an angle to the neutral axis of thereverse gear when said piston is on dead center that the effect on thevalve of angular distortions in the motion of the rock arm iseliminated.

2. In a valve gear for a reciprocating pis actuating mechanism thereforintroducing angular distortions in the motion thereof, and meansconnecting said rock arm with the engine valve including a reverse gearof the Marshall type, said rock arm having its longitudinal axisarranged non-parallel to the neutral axis of said reverse gear when saidpiston is on dead center.

3. In a valve gear, the combination with a reciprocating actuatingmember having its movement distorted from a simple harmonic movement, ofa reciprocatory valve and means intermediate said reciprocatingactuating member and reciprocatory valve for transmitting an equalmovement to the latter on opposite sides of the center reversible indirection and variable in amplitude, said means including a rock armreceiving motion from said actuating member, a reversing gear of theMarshall-type and a connection between said rock-arm and reversing gear,the longitudinal axis of said rock arm and the longitudinal axis of thereversing gear in neutral position being non-parallel when the engine ison dead center.

4. In avalve gear,the combination with an actuating mechanism for anengine valve, introducing angular distortions and a rock arm, of apivoted yoke, a bell-crank lever, links pi'votally connecting said yokeand bell-crank lever, and a rod connecting said rock arm and links, thelongitudinal axis of said rock arm and one of said links diverging whenthe yoke is in neutral position and the engine is on dead center wherebythe angular distortions are corrected and the valve movement is uniformon opposite sides of the center.

In testimony whereof I aflix my signature in presence of two witnesses.

' CHARLES J. PILLIOD.

Witnesses: JAMES P. BARRY,

H. E. BOWMAN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

